CHARACTERIZATION OF A LIQUID-METAL MICRO DROPLETS THERMAL INTERFACE MATERIAL

This work presents the characterization of a thermal interface material consisting of an array of mercury micro droplets deposited on a silicon die. Three arrays were tested, a 40 x 40 array (1600 grid) and two 20 x 20 arrays (400 grid). All arrays were assembled on a 4 x 4 mm(2) silicon die. An experimental facility which measures the thermal resistance across the mercury array under steady state conditions is described. The thermal interface resistance of the arrays was characterized as a function of the applied load. A thermal interface resistance as low as 0.253 mm(2) K W-1 was measured. A model to predict the thermal resistance of a liquid-metal micro droplet array was developed and compared to the experimental results. The model predicts the deformation of the droplet array under an applied load and then the geometry of the deformed droplets is used to predict the thermal resistance of the array. The contact resistance of the mercury arrays was estimated based on the experimental and model data. An average contact resistance was estimated to be 0.14 mm(2) K W-1.